Insertion assisting tool for endoscope

ABSTRACT

An insertion assisting tool for an endoscope into which an insertion section of the endoscope is inserted from a base end portion side, comprising: a fluid sealing device which seals a space between a base end part of the insertion assisting tool and the endoscope insertion section, the space being formed while the insertion section of the endoscope is inserted into the base end portion side.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an insertion assisting tool for anendoscope, and particularly, relates to an insertion assisting tool ofan endoscope which is used when an insertion section of the endoscope isinserted into a body cavity.

2. Description of the Related Art

When the insertion section of an endoscope is inserted into a deepalimentary canal such as a small intestine, by only pushing theinsertion section into the deep alimentary canal, the force is difficultto transmit to a tip end of the insertion section due to complicatedbending of an intestinal canal, and insertion into a deep part isdifficult. Namely, if excessive bending and deflection occur to theinsertion section, it is difficult to insert the insertion sectionfurther into a deeper part. Thus, there is proposed an endoscopeapparatus which prevents excessive bending and deflection of theinsertion section by inserting the insertion section into a body cavitywith an insertion assisting tool called an over tube or a sliding tubeattached to the insertion section of the endoscope, and inserting theinsertion section into the body cavity while guiding the insertionsection with this insertion assisting tool (for example, Japanese PatentApplication Publication No. 10-248794).

Meanwhile, a double balloon type endoscope apparatus disclosed inJapanese Patent Application Publication No. 2002-301019 includes anendoscope with an inflatable and deflatable balloon attached to a tipend peripheral portion of an endoscope insertion section, and an overtube which serves as a guide at the time of insertion of the insertionsection, with an inflatable and deflatable balloon attached to the tipend peripheral portion, and the endoscope insertion section insertedinto the over tube. This double balloon type endoscope apparatus is forinserting the endoscope insertion section into a deep part of analimentary canal by carrying out an insertion operation of the over tubeand the endoscope insertion section and the inflation and deflationoperations of the two balloons in accordance with a predeterminedprocedure.

SUMMARY OF THE INVENTION

However, the insertion assisting tool in Japanese Patent ApplicationPublication No. 10-248794 has the problem that when the insertionassisting tool is inserted into a body cavity, a body fluid flowsbackward from a gap between the insertion assisting tool and theinsertion section due to internal pressure of the body cavity, and leaksoutside from a base end opening of the insertion assisting tool.

Similarly, the over tube of the double balloon type endoscope apparatusof Japanese Patent Application Publication No. 2002-301019 also has theproblem that when the over tube is inserted into the body cavity, thebody fluid flows backward from a gap between the over tube and theendoscope insertion section due to internal pressure of the body cavity(alimentary canal), and leaks outside from a base end opening of theover tube.

The present invention is made in view of the above circumstances, andhas its object to provide an insertion assisting tool of an endoscopecapable of preventing leakage of a fluid flowing backward from a bodycavity.

In order to attain the above-described object, a first aspect of thepresent invention is, in an insertion assisting tool for an endoscopeinto which an insertion section of the endoscope is inserted from a baseend portion side, comprising:

a fluid sealing device which seals a space between a base end part ofthe insertion assisting tool and the endoscope insertion section, thespace being formed while the insertion section of the endoscope isinserted into the base end portion side.

According to the first aspect, the liquid sealing device is provided,and therefore, a body fluid and a fluid such as a lubricating liquid,which is supplied to the insertion assisting tool, can be prevented fromleaking from the space between the base end part of the insertionassisting tool and the endoscope insertion section.

In order to attain the aforesaid object, a second aspect of the presentinvention is, in an insertion assisting tool into which an insertionsection of an endoscope is inserted, characterized by including a liquidstoring part formed at a base end part side of the insertion assistingtool.

According to the second aspect, during an operation in which theinsertion assisting tool is inserted into a body cavity, the body fluid,which flows backward from the gap between the insertion assisting tooland the insertion section due to internal pressure of the body cavity,is stored in the liquid storing part formed at the side of the base endpart of the insertion assisting tool, and therefore, leakage of the bodyfluid flowing backward can be prevented.

According to a third aspect of the present invention, the insertionassisting section is characterized in that a suction device is attachedto the liquid storing part of the insertion assisting tool. By attachingthe suction device to the liquid storing part like this, the body fluidstored in the liquid storing part can be discharged from the liquidstoring part, and therefore, leakage from the liquid storing part due tooverflow can be prevented.

According to a fourth aspect of the present invention, the insertionassisting tool is characterized in that a liquid absorbing member ishoused in the liquid storing part of the insertion assisting tool, andthe liquid storing part is detachably attached to an insertion assistingtool body. The liquid absorbing member such as a sponge is housed in theliquid storing part, and thereby, the body fluid stored in the liquidstoring part is held by the liquid absorbing member. Thereby, leakage ofthe body fluid from the liquid storing part can be prevented when theinsertion assisting tool is used upside down due to the motion duringoperation. The liquid absorbing member which sufficiently absorbs thebody fluid is removed by detaching the liquid storing part from theinsertion assisting tool body, and is replaced with a new liquidabsorbing member, thus making it possible to use the insertion assistingtool repeatedly.

According to a fifth aspect of the present invention, an inflatable anddeflatable balloon is attached to an insertion section of the endoscopeand/or a tip end part of the insertion assisting tool. The insertionassisting tool can be fixed to a body wall by inflating the balloon andclosely fitting the balloon to the body wall such as an intestinal wall.In this state, the body wall is observed while performing a curvingoperation of the curving part of the endoscope insertion section, whichprotrudes from the tip end part of the insertion assisting tool, withthe hand operation section. At this time, the insertion assisting toolis fixed to the body wall, and therefore, there is no fear that thecurving part and the tip end part of the insertion section contact theinsertion assisting tool, whereby curving operability of the curvingpart is enhanced. The insertion assisting tool having the balloon can beapplied to a double-balloon type endoscope apparatus which uses theinsertion assisting tool having the balloon by fitting the insertionassisting tool onto the endoscope insertion section also having aballoon. This endoscope apparatus makes it possible to observe anintestine by drawing in the intestine by carrying out the inflating anddeflating operation of the two balloons, the insertion and extractionoperation of the endoscope insertion section, and the insertion andextraction operation of the insertion assisting tool in accordance witha predetermined procedure.

In order to attain the above-described object, a sixth aspect of thepresent invention is characterized in that a cylindrical extendable andcontractible member connecting respective base end parts of an insertionsection of the endoscope and the insertion assisting tool in which theinsertion section of the endoscope is inserted, said cylindricalextendable and contractible member covering the insertion section.

According to the sixth aspect of the invention, the respective base endparts of the insertion section of the endoscope and the insertionassisting tool into which the insertion section is inserted areconnected by the cylindrical extendable and contractible member whichcovers the insertion section, and therefore, the body fluid flowingbackward from the gap between the insertion assisting tool and theinsertion section does not leak. Thereby, the leakage of the body fluidflowing backward from the body cavity can be prevented. Since theextendable and contractible member extends and contracts, the insertionoperation and drawing-in operation of the insertion assisting tool andthe insertion section can be performed smoothly.

According to a seventh aspect of the present invention, the insertionassisting tool is characterized in that the extendable and contractiblemember is an accordion-shaped member. Thereby, the extendable andcontractible member can be easily constructed.

According to an eighth aspect of the present invention, the insertionassisting tool is characterized in that the extendable and contractiblemember is formed to have length by which a tip end part of the insertionassisting tool does not contact a first balloon of the insertion sectionwhen the extendable and contractible member is operated to extend most.As a result, at the stroke end when the insertion assisting tool isinserted deepest, the tip end part of the insertion assisting tool doesnot contact the first balloon, and therefore, the first balloon is notbroken by contact of the tip end part of the insertion assisting tool.As for restraint at the time of the extension of the extendable andcontractible member, the restraint can be achieved by setting the lengthand the number of the pleats of the accordion shape in the case of theaccordion-shaped member having directivity in one direction in theextending and contracting direction. On the other hand, in the case of,for example, a bag-shaped member having no directivity in the extendingand contracting direction, the restraint can be achieved by attachingrestraining linear elements such as wires and strings, which restrainthe extension amount, to the bag-shaped member.

According to a ninth aspect of the present invention, the insertionassisting tool is characterized in that a drain port is formed in theextendible member. The body fluid stored in the gap between theextendable and contractible member and the insertion section can bedischarged to the outside from the gap via the drain port. A pump isseparately connected to the drain port, and the liquid can be alsodischarged by the power of the power. Further, the body fluid stored inthe gap may be discharged from the drain port by the pumping actionoccurring when the extendable and contractible member extends andcontracts.

In order to achieve the above-described object, a tenth aspect of thepresent invention is, in the insertion assisting tool into which aninsertion section of the endoscope is inserted, characterized byincluding a substantially cylindrical tube formed of an elastic body inwhich a smaller opening than a diameter of a base end part of theinsertion assisting tool is formed at one end and a smaller opening thana diameter of the endoscope insertion section is formed at the otherend, and characterized in that in the tube, the opening formed at theone end is attached to the base end part of the insertion assisting toolin close contact with the base end part, and the insertion section ofthe endoscope is slidably inserted through the tube with the insertionsection of the endoscope closely fitted in the opening formed at theother end.

According to the tenth aspect, the opening formed at one end of the tubeis attached to the base end part of the insertion assisting tool inclose contact with the base end part by the elastic force, and theinsertion section of the endoscope is slidably inserted through theopening in close contact with the opening formed at the other end of thetube by the elastic force. During the operation in which the insertionassisting tool is inserted into the body cavity, the body fluid flowingbackward from the gap between the insertion assisting tool and theinsertion section due to the internal pressure of the body cavity isstored in the tube without leaking from the tube. Namely, both ends ofthe tube are attached to the parts respectively in close contact withthe parts by the elastic force, and therefore, the tube exhibits thefunction of the check valve. Thereby, the leakage of the body fluid canbe prevented. In the case of the insertion assisting tool enhanced inslip property of the insertion section for the insertion assisting toolby supplying the lubricating liquid into the gap between the insertionassisting tool and the insertion section, it becomes possible to fillthe lubricating liquid in the gap by allowing the tube to have the potfunction of storing the lubricating liquid, and therefore, favorableslip property can be always obtained. Further, the supply amount and thenumber of supply times of the lubricating liquid can be reduced by thelubricating liquid pot function of the tube.

An eleventh aspect of the present invention is the invention whichenhances the insertion and extraction operability of the insertionsection with respect to the insertion assisting tool in the case wherethe tube is fitted to the aforesaid parts. The insertion section isinserted into the base end part of the insertion assisting tool withsome degree of freedom. Namely, the space between the base end part ofthe insertion assisting tool and the insertion section is set to becomparatively larger than the spaces at the other positions, and theinsertion and extraction operability of the operator is enhanced bymaking the insertion and extraction direction of the insertion sectionproperly changeable by using the space. Accordingly, in the case wherethe tube is fitted, it is also necessary to keep this insertion andextraction operability.

Thus, according to the eleventh aspect, the insertion assisting tool ischaracterized in that the tube is formed in a size which satisfies aformula: d>a−c+(b−a)/2 where an inner diameter of the insertionassisting tool is a, a maximum diameter of the tube when the tube isattached to the insertion assisting tool is b, a diameter of an openingformed at the other end of the tube is c, and a distance from a fixedportion of the tube to the insertion assisting tool to an edge portionof the opening formed at the other end of the tube is d. As a result,when the insertion section is put aside as much as possible by using thespace, the tube does not have tension, but has slack, and therefore, theinsertion and extraction operability of the tube can be maintained.

According to the insertion assisting tool of the endoscope according tothe present invention, the fluid sealing device which seals the spacebetween the base end part of the insertion assisting tool and theinsertion section of the endoscope, and prevents the fluid from leakingis provided, and therefore, the fluid can be prevented from leaking fromthe space between the base end part of the insertion assisting tool andthe insertion section.

According to the insertion assisting tool of the endoscope according tothe present invention, the body fluid flowing backward from the gapbetween the insertion assisting tool and the insertion section is storedin the liquid storing part formed at the base end part side of theinsertion assisting tool, and therefore, leakage of the body fluidflowing backward can be prevented.

Further, according to the insertion assisting tool of the endoscopeaccording to the present invention, the space between the insertionassisting tool and the insertion section is covered with the extendableand contractible member, and therefore, leakage of the body fluidflowing backward from the inside of the body cavity can be prevented. Inaddition, the extendable and contractible member extends and contracts,and therefore, the insertion operation and drawing-in operation of theinsertion assisting tool and the insertion section can be smoothlyperformed.

According to the insertion assisting tool of the endoscope according tothe present invention, the body fluid flowing backward from the spacebetween the insertion assisting tool and the insertion section is storedin the tube having the function of the check valve, and therefore, theleakage of the body fluid flowing backward can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a system schematic diagram of an endoscope apparatus accordingto the present invention;

FIG. 2 is a perspective view showing a tip end part of an insertionsection of an endoscope;

FIG. 3 is a perspective view showing the tip end part of the insertionsection onto which a first balloon is fitted;

FIG. 4 is a sectional side view showing an over tube;

FIG. 5 is a sectional side view showing a tip end portion of the overtube through which the insertion section is inserted;

FIGS. 6A to 6H are explanatory views showing an operation method of theendoscope apparatus according to the present invention;

FIG. 7 is a partially enlarged sectional view showing another example ofthe over tube;

FIG. 8 is a system schematic diagram of an endoscope apparatus to whichthe over tube according to the present invention is applied;

FIG. 9 is a perspective view showing a tip end part of an insertionsection of the endoscope;

FIG. 10 is a perspective view showing a tip end rigid part of theinsertion section onto which the first balloon is fitted;

FIG. 11 is a side view of the over tube;

FIG. 12 is a sectional side view showing the tip end part of the overtube through which the insertion section is inserted;

FIG. 13 is a sectional side view of the over tube which is fitted ontothe endoscope insertion section;

FIGS. 14A and 14B are explanatory views showing a stroke of anaccordion-shaped extendable and contractible member of the over tube;

FIGS. 15A to 15H are explanatory views showing an operation method ofthe endoscope apparatus shown in FIG. 1;

FIGS. 16A and 16B are explanatory views showing an operation of abag-shaped member of the over tube;

FIGS. 17A and 17B are sectional side views of the over tube providedwith a drain port at the accordion-shaped extendable and contractiblemember of the over tube;

FIG. 18 is a system schematic diagram of an endoscope apparatusaccording to the present invention;

FIG. 19 is a perspective view showing the tip end part of the insertionsection of the endoscope;

FIG. 20 is a perspective view showing the tip end part of the insertionsection of the endoscope;

FIG. 21 is a sectional side view showing the over tube;

FIG. 22 is a sectional view of a tube attached to the gripping part ofthe over tube;

FIG. 23 is a perspective view of the over tube and the tube;

FIGS. 24A to 24C are explanatory views showing insertion and extractionoperation of the insertion section with respect to the tube;

FIGS. 25A to 25H are explanatory views showing an operation method ofthe endoscope apparatus according to the present invention; and

FIG. 26 is a schematic diagram for explaining the size of the tube.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of an insertion assisting tool of an endoscopeaccording to the present invention will be explained in accordance withthe following attached drawings.

FIG. 1 shows a system schematic diagram of an endoscope apparatus towhich an insertion assisting tool according to a first embodiment of thepresent invention is applied. The endoscope apparatus shown in thedrawing is constructed by an endoscope 10, an over tube (correspondingto the insertion assisting tool) 50, and a balloon control device 100.

The endoscope 10 includes a hand operation section 14, and an insertionsection 12 connected to the hand operation section 14. A universal cable15 is connected to the hand operation section 14, and a connecter (notshown) connected to a processor and a light source device not shown isprovided at a tip end of the universal cable 15.

On the hand operation section 14, an air/water passing button 16, asuction button 18, and a shutter button 20 which are operated by anoperator are provided in parallel, and a pair of angle knobs 22 and 22,and a forceps insertion part 24 are respectively provided atpredetermined positions. Further, the hand operation section 14 isprovided with a balloon air port 26 for supplying air to a first balloon30 and sucking air from the balloon 30.

The insertion section 12 is constructed by a flexible part 32, a curvingpart 34 and a tip end part 36. The curving part 34 is constructed byconnecting a plurality of node rings to be able to curve, and isremotely operated to curve by the rotational operation of a pair ofangle knobs 22 and 22 provided on the hand operation section 14.Thereby, a tip end surface 37 of the tip end part 36 can be directed ina desired direction.

As shown in FIG. 2, the tip end surface 37 of the tip end part 36 isprovided with an object optical system 38, an illumination lens 40, anair/water passing nozzle 42, a forceps port 44 and the like inpredetermined positions. An air supply/suction port 28 is provided on anouter peripheral surface of the tip end part 36, and this airsupply/suction port 28 communicates with the balloon air port 26 in FIG.1 via an air supply tube (not shown) with an inner diameter of about 0.8mm which is inserted into the insertion section 12. Accordingly, air isblown out of the air supply/suction port 28 of the tip end part 36 bysupplying air to the balloon air port 26, and on the other hand, air issucked from the air supply/suction port 28 by sucking air from theballoon air port 26.

As shown in FIG. 1, the first balloon 30 constituted of an elastic bodysuch as rubber is detachably attached to the tip end part 36 of theinsertion section 12. The first balloon 30 is formed by a bulgingportion 30 c in a center and attaching portions 30 a and 30 b at bothends of the bulging portion 30 c, and is attached to the tip end part 36side so that the air supply/suction port 28 is located inside thebulging portion 30 c as shown in FIG. 3. The attaching portions 30 a and30 b are formed to have smaller diameters than the diameter of the tipend part 36, and after being closely fitted onto the tip end part 36with their elastic forces, the attaching portions 30 a and 30 b arefixed with threads not shown wound around the attaching portions 30 aand 30 b. The fixation is not limited to the thread winding fixation,but the attaching portions 30 a and 30 b may be fixed to the tip endpart 36 by fitting fixing rings onto the attaching portions 30 a and 30b.

The first balloon 30 fitted onto the tip end part 36 has its bulgingportion 30 c inflated in a substantially spherical shape by blowing airfrom the air supply/suction port 28 shown in FIG. 2. On the other hand,by sucking air from the air supply/suction port 28, the bulging portion30 c is deflated and is closely fitted onto the outer peripheral surfaceof the tip end part 36.

The over tube 50 shown in FIG. 1 is formed by a tube body 51, and agripping part 52 in which a liquid storing part 53 is formed. The tubebody 51 is formed into a cylindrical shape and has a slightly largerinner diameter than an outer diameter of the insertion section 12, asshown in FIGS. 4 and 5. The tube body 51 is constructed by covering anouter side of a flexible resin tube made of urethane or the like withlubricating coat and covering an inner side with the lubricating coat. Aconnecting port 52A formed at a tip end of the rigid gripping part 52 isfitted onto a base end opening 51A of the tube body 51 in a watertightstate, and the gripping part 52 is constructed to be attachable anddetachable with respect to the tube body 51. The insertion section 12 isinserted toward the tube body 51 from the base end opening 52B of thegripping part 52.

As shown in FIG. 4, a balloon air port 54 is provided at the base endside of the tube body 51. An air supply tube 56 with an inner diameterof about 1 mm is connected to the balloon air port 54, and this tube 56is bonded to an outer peripheral surface of the tube body 51 and isprovided to extend to a tip end portion of the tube body 51.

A tip end 58 of the tube body 51 is formed into a tapered shape. Asecond balloon 60 constituted of an elastic body such as rubber isfitted onto the base end side of the tip end 58 of the tube body 51. Thesecond balloon 60 is fitted in the state in which the tube body 51penetrates through the balloon 60, and is constructed by a bulgingportion 60 c in a center, and attaching portions 60 a and 60 b at bothends of the bulging portion 60 c. The attaching portion 60 a at the tipend side is folded back to the inside of the bulging portion 60 c, andthe attaching portion 60 a folded back is fixed to the tube body 51 withan X-ray contrast thread 62 wound around the attaching portion 60 awhich is folded back. The attaching portion 60 b at the base end side isdisposed outside the second balloon 60, and is fixed to the tube body 51with a thread 64 wound around the attaching portion 60 b.

The bulging portion 60 c is formed into a substantially spherical shapein a natural state (the state in which the bulging portion 60 c does notinflate or deflate), and as for the size, the bulging portion 60 c isformed to be larger than the size of the first balloon 30 in a naturalstate (the state in which the balloon 30 does not inflate or deflate).Accordingly, when the air is supplied to the first balloon 30 and thesecond balloon 60 at the same pressure, the outer diameter of thebulging portion 60 c of the second balloon becomes larger than the outerdiameter of the bulging portion 30 c of the first balloon 30. The outerdiameter of the second balloon 60 is constructed so as to be φ50 mm whenthe outer diameter of the first balloon 30 is φ25 mm, for example.

The aforementioned tube 56 is opened in the inside of the bulgingportion 60 c, and an air supply/suction port 57 is formed. Accordingly,when air is supplied from the balloon air port 54, the air is blown fromthe air supply/suction port 57 and thereby, the bulging portion 60 c isinflated. When air is sucked from the balloon air port 54, the air issucked from the air supply/suction portion 57, and the second balloon 60is deflated. Reference numeral 66 in FIG. 4 designates an inlet port forfilling a lubricant such as water into the tube body 51, and the inletport 66 communicates with the vicinity of a connecting port 52A formedat a tip end of the gripping part 52 via a tube 68 with a thin diameter.

The liquid storing part 53 of the gripping part 52 is formed into aspherical shape having a larger diameter than the diameter of the tubebody 51, and an arc-shaped recessed portion 80 is formed inside theliquid storing part 53. A sponge (liquid absorbing member) 82 formedinto a donut shape is hosed in this recessed portion 80. The innerdiameter of the sponge 82 is formed to be larger than the outer diameterof the insertion section 12, and therefore, it causes no problem ininsertion of the insertion section 12. On the other hand, when liquidleakage is prevented by an O-ring or the like, the O-ring has to befastened to the insertion section 12, which causes the problem ofimpairing insertion easiness, and the present example can solve such aproblem. The shape of the sponge is not limited to the donut shape, butthe sponge may be formed into a substantially cylindrical shape. Byforming a split in the sponge formed into the donut shape orsubstantially cylindrical shape, the insertion section 12 can be removedfrom the sponge via the split in the state in which the insertionsection 12 is inserted through the sponge.

At the time of an operation, the body fluid which flows backward from agap between the tube body 51 and the insertion section 12 stays in therecessed portion 80 and absorbed in the sponge 82, thus preventing theliquid leakage from the recessed portion 80. A water intake port 86communicates with the recessed portion 80 of the liquid storing part 53via a thin-diameter tube 84, and by connecting a suction device such asan injector and a pump to this water intake port 86, and making thesuction device perform a suction operation, the liquid stored in therecessed portion 80, and the liquid absorbed in the sponge 82 is suckedand removed from the liquid storing part 53.

Meanwhile, the balloon control device 100 in FIG. 1 is the device whichsupplies and sucks fluid such as air to and from the first balloon 30,and supplies and sucks fluid such as air to and from the second balloon60. The balloon control device 100 is constructed by a device body 102including a pump, a sequencer and the like not shown, and a hand switch104 for remote control.

A front panel of the device body 102 is provided with a power supplyswitch SW1, a stop switch SW2, a pressure gauge 106 for the firstballoon 30 and a pressure gauge 108 for the second balloon 60. A tube110 for supplying/sucking air to and from the first balloon 30, and atube 120 for supplying/sucking air to and from the second balloon 60 areattached to the front panel of the device body 102. Liquid storing tanks130 and 140 for storing body fluid, which flows backward from the firstballoon 30 and the second balloon 60 when the first balloon 30 and thesecond balloon 60 are broken, are respectively provided at midpoints ofthe respective tubes 110 and 120.

Meanwhile, the hand switch 104 is provided with a similar stop switchSW3 to the stop switch SW2 at the side of the device body 102, an ON/OFFswitch SW4 for supporting pressurization/decompression of the firstballoon 30, a pose switch SW5 for keeping the pressure of the firstballoon 30, an ON/OFF switch SW6 for supportingpressurization/decompression of the second balloon 60, and a pose switchSW7 for keeping the pressure of the second balloon 60. This hand switch104 is electrically connected to the device body 102 via a cable 150.

The balloon control device 100 thus constructed supplies air to thefirst balloon 30 and the second balloon 60 and inflates the firstballoon 30 and the second balloon 60, and controls the air pressure at afixed value to keep the first balloon 30 and the second balloon 60 inthe inflated state. The balloon control device 100 sucks air from thefirst balloon 30 and the second balloon 60 and deflates the firstballoon 30 and the second balloon 60, and controls the air pressure at afixed value to keep the first balloon 30 and the second balloon 60 inthe deflated state.

Next, an operation method of the endoscope apparatus will be explainedin accordance with FIGS. 6A to 6H.

First, as shown in FIG. 6A, the insertion section 12 is inserted into anintestinal canal (for example, descending limb of duodenum) 70 in thestate in which the over tube 50 covers the insertion section 12. At thistime, the first balloon 30 and the second balloon 60 are deflated.

Next, as shown in FIG. 6B, in the state in which the tip end 58 of theover tube 50 is inserted into a bent portion of the intestinal canal 70,air is supplied to the second balloon 60 to inflate the second balloon60. As a result, the second balloon 60 is caught by the intestinal canal70, and the tip end 58 of the over tube 50 is fixed to the intestinalcanal 70.

Next, as shown in FIG. 6C, only the insertion section 12 of theendoscope 10 is inserted to a deep part of the intestinal canal 70.Then, as shown in FIG. 6D, air is supplied to the first balloon 30 toinflate the first balloon 30. As a result, the first balloon 30 is fixedto the intestinal canal 70. In this case, the first balloon 30 issmaller in the size at the time of inflation than the second balloon 60,and therefore the burden exerted on the intestinal canal 70 is small,thus making it possible to prevent damage to the intestinal canal 70.

Next, after air is sucked from the second balloon 60 to deflate thesecond balloon 60, the over tube 50 is pushed in, and inserted along theinsertion section 12, as shown in FIG. 6E. Then, after the tip end 58 ofthe over tube 50 is pushed into the vicinity of the first balloon 30,air is supplied to the second balloon 60 to inflate the second balloon60 as shown in FIG. 6F. As a result, the second balloon 60 is fixed tothe intestinal canal 70. Namely, the intestinal canal 70 is gripped bythe second balloon 60.

Next, as shown in FIG. 6G, the over tube 50 is drawn in. Thereby, theintestinal canal 70 contracts substantially straight, and excessivedeflection and bending of the over tube 50 are eliminated. When the overtube 50 is drawn in, both the first balloon 30 and the second balloon 60are caught in the intestinal canal 70, but the friction resistance ofthe first balloon 30 is smaller than the friction resistance of thesecond balloon 60. Therefore, even if the first balloon 30 and thesecond balloon 60 move to relatively separate, the first balloon 30 withsmall friction resistance slides with respect to the intestinal canal70, and therefore, it does not happen that the intestinal canal 70 isdamaged by being pulled by both the balloons 30 and 60.

Next, as shown in FIG. 6H, air is sucked from the first balloon 30 todeflate the first balloon 30. Then, the tip end part 36 of the insertionsection 12 is inserted into as deep a part of the intestinal canal 70 aspossible. Namely, the insertion operation as shown in FIG. 6C isperformed again. Thereby, the tip end part 36 of the insertion section12 can be inserted into a deep part of the intestinal canal 70. When theinsertion section 12 is further inserted into a deep part, the pushingoperation as shown in FIG. 6E is performed after the fixing operation asshown in FIG. 6D is performed, the gripping operation as shown in FIG.6F and the drawing-in operation as shown in FIG. 6G, and the insertingoperation as shown in FIG. 6H are repeatedly performed in sequence.Thus, the insertion section 12 can be further inserted into a deep partof the intestinal canal 70.

During such an operation, the body fluid which flows backward from thegap between the tube body 51 of the over tube 50 and the insertionsection 12 (see FIG. 4) due to the internal pressure of the intestinalcanal 70 stays in the recessed portion 80 of the liquid storing part 53formed in the gripping part 52, and therefore, the body fluid flowingbackward can be prevented from leaking from the base end opening 52B ofthe gripping part 52.

The body fluid stored in the liquid storing part 53 can be dischargedfrom the liquid storing part 53 by sucking the body fluid stored in theliquid storing part 53 by the suction device such as an injectorconnected to the suction port 86, and therefore, leakage of the bodyfluid from the liquid storing part 53 due to overflow can be prevented.

Further, the sponge 82 is housed in the liquid storing part 53, andtherefore, the body fluid stored in the liquid storing part 53 can beheld by the sponge 82. Therefore, leakage of the body fluid from theliquid storing part 53 when the over tube 50 is used upside down in themotion during operation can be prevented. The sponge 82 whichsufficiently absorbs the body fluid is taken out of the liquid storingpart 53 after the gripping part 52 is detached from the tube body 51,and exchanged with a new sponge 82. Thus, the repeated use of thegripping part 52 is possible.

In the embodiment, the example of the over tube 50 having the balloon isexplained, but the present invention can be also applied to a slidingtube which guides the endoscope insertion section into a body cavitywithout a balloon. The structure of the gripping part 52 is not limitedto the example in FIG. 4, but as shown in FIG. 7, an opening 88 foropening the liquid storing part 53 is formed in order to make it easy toremove the sponge 82 from the recessed portion 80, and a donut-shapedcap 90 may be detachably fitted to the opening 88. According to thisstructure, the sponge 82 can be easily removed from the recessed portion80 by only taking the cap 90 from the opening 88.

FIG. 8 shows a system schematic diagram of an endoscope apparatus towhich an over tube according to a second embodiment of the presentinvention is applied. The endoscope apparatus shown in the drawing isconstructed by an endoscope 110, an over tube 150, and a balloon controldevice 1100.

The endoscope 110 includes a hand operation section 114, and aninsertion section 112 connected to the hand operation section 114. Auniversal cable 115 is connected to the hand operation section 114, anda connecter (not shown) connected to a processor and a light sourcedevice not shown is provided at a tip end of the universal cable 115.

On the hand operation section 114, an air/water passing button 116, asuction button 118, and a shutter button 120 which are operated by anoperator are provided in parallel, and a pair of angle knobs 122 and 122and a forceps insertion section 124 are respectively provided inpredetermined positions. Further, the hand operation section 114 isprovided with a balloon air port 126 for supplying air to a firstballoon 130 and sucking air from the first balloon 130.

The insertion section 112 is constructed by a flexible part 132, acurving part 134 and a tip end rigid part 136. The curving part 134 isconstructed by connecting a plurality of node rings to be able to curve,and is remotely operated to curve by the rotational operation of a pairof angle knobs 122 and 122 provided on the hand operation section 114.Thereby, a tip end surface 137 of the tip end part 136 can be directedin a desired direction.

As shown in FIG. 9, the tip end surface 137 of the tip end part 136 isprovided with an object optical system 138, an illumination lens 140, anair/water passing nozzle 142, a forceps port 144 and the like inpredetermined positions. An air supply/suction port 128 is provided onan outer peripheral surface of the tip end part 136, and this airsupply/suction port 128 communicates with the balloon air port 126 inFIG. 8 via an air supply tube (not shown) with an inner diameter ofabout 0.8 mm which is inserted into the insertion section 112.Accordingly, air is blown out of the air supply/suction port 128 of thetip end part 136 by supplying air to the balloon air port 126, and onthe other hand, air is sucked from the air supply/suction port 128 bysucking air from the balloon airport 126.

As shown in FIG. 8, a first balloon 130 constituted of an elastic bodysuch as rubber is detachably attached to the tip end part 136 of theinsertion section 112. The first balloon 130 is formed by a bulgingportion 130 c in a center and attaching portions 130 a and 130 b at bothends of the bulging portion 130 c, and is attached to the tip end part136 side so that the air supply/suction port 128 is located inside thebulging portion 130 c as shown in FIG. 10. The attaching portions 130 aand 130 b are formed to have smaller diameters than the diameter of thetip end portion 136, and after being closely fitted onto the tip endpart 136 with their elastic forces, the attaching portions 130 a and 130b are fixed with threads not shown wound around the attaching portions130 a and 130 b. The fixation is not limited to the thread windingfixation, but the attaching portions 130 a and 130 b may be fixed to thetip end part 136 by fitting fixing rings onto the attaching portions 130a and 130 b.

The first balloon 130 fitted onto the tip end part 136 has its bulgingportion 130 c inflated into a substantially spherical shape by blowingair from the air supply/suction port 128 shown in FIG. 9. On the otherhand, by sucking air from the air supply/suction port 128, the bulgingportion 130 c is deflated and is closely fitted onto the outerperipheral surface of the tip end part 136.

The over tube 150 shown in FIG. 8 is formed by a tube body 151, and anaccordion-shaped extendable and contractible member 152. The tube body151 is formed into a cylindrical shape and has a slightly larger innerdiameter than an outer diameter of the insertion section 112, as shownin FIGS. 4 and 5. The tube body 151 is constructed by coveting an outerside of a flexible resin tube made of urethane or the like withlubricating coat and covering an inner side with the lubricating coat.

The accordion-shaped extendable and contractible member 152 is made of aflexible resin material constituted of urethane or the like, and aring-shaped fitting member 153, which is fixed to a tip end of theaccordion-shaped extendable and contractible member 152, is fitted(connected) onto a base end opening 151A of the tube body 151 in thewatertight state. A ring-shaped fitting member 155 fixed to a base endportion of the accordion-shaped extendable and contractible member 152is fitted onto (connected to) a fold preventing part (base part of theinsertion section) 117 in a substantially circular conical shape, whichis formed at the tip end of the hand operating section 114, in thewatertight state via a packing 159 as shown in FIG. 13. Thereby, therespective base end portions of the over tube 150 and the insertionsection 112 are connected by the accordion-shaped extendable andcontractible member 152. By using taper surface of the fold preventingpart 117, fitting of the ring-shaped fitting member 155 can be easilyperformed in the water tight state.

As shown in FIG. 8, a balloon air port 154 is provided at the base endside of the tube body 151. An air supply tube 156 with an inner diameterof about 1 mm is connected to the balloon air port 154, and this tube156 is bonded to an outer peripheral surface of the tube body 151 and isprovided to extend to a tip end portion of the tube body 151, as shownin FIGS. 11 and 12.

A tip end 158 of the tube body 151 is formed into a tapered shape. Asecond balloon 160 constituted of an elastic body such as rubber isfitted onto the base end side of the tip end 158 of the tube body 151.The second balloon 160 is fitted in the state in which the tube body 151penetrates through the balloon 160 as shown in FIG. 12, and isconstructed by a bulging portion 160 c, and attaching portions 160 a and160 b at both ends of the bulging portion 160 c. The attaching portion160 a at the tip end side is folded back to the inside of the bulgingportion 160 c, and the attaching portion 160 a that is folded back isfixed to the tube body 151 with an X-ray contrast thread 162 woundaround the attaching portion 160 a that is folded back. The attachingportion 160 b at the base end side is disposed outside the secondballoon 160, and is fixed to the tube body 151 with a thread 164 woundaround the attaching portion 160 b.

The bulging portion 160 c is formed into a substantially spherical shapein a natural state (the state in which the bulging portion 160 c doesnot inflate or deflate), and as for the size, the bulging portion 160 cis formed to be larger than the size of the first balloon 130 in anatural state (the state in which the balloon 130 does not inflate ordeflate). Accordingly, when the air is supplied to the first balloon 130and the second balloon 160 at the same pressure, the outer diameter ofthe bulging portion 160 c of the second balloon 160 becomes larger thanthe outer diameter of the bulging portion 130 c of the first balloon130. The outer diameter of the second balloon 160 is constructed so asto be φ50 mm when the outer diameter of the first balloon 130 is φ25 mm,for example.

The aforementioned tube 156 is opened in the inside of the bulgingportion 160 c, and an air supply/suction port 157 is formed.Accordingly, when air is supplied from the balloon air port 154, the airis blown from the air supply/suction port 157 and thereby, the bulgingportion 160 c is inflated. When air is sucked from the balloon air port154, the air is sucked from the air supply/suction port 157, and thesecond balloon 160 is deflated.

Reference numeral 166 in FIG. 11 designates an inlet port for filling alubricating liquid such as water into the tube body 151, and the inletport 166 communicates with the base end portion side of the tube body151 via a tube 168 with a thin diameter.

Incidentally, the accordion-shaped extendable and contractible member152 is repeatedly extended and contracted between the most extendedstate shown in FIG. 14A and the most contracted state shown in FIG. 14Bduring operation of the endoscope. Here, in setting the length of theaccordion-shaped extendable and contractible member 152, the length isset so that a difference A between the most extended time and the mostcontracted time of the accordion-shaped extendable and contractiblemember 152 satisfies a moving amount B necessary for the operation ofthe endoscope (for example, 40 cm<A<60 cm), and keeps a space C by whichthe tip end 158 of the over tube 150 dose not abut to the first balloon130 at the most extended time. The length of the accordion-shapedextendable and contractible member 152 is adjusted by the length of thepleat and the number of pleats of the accordion-shaped member.

Meanwhile, the balloon control device 1100 in FIG. 8 is the device whichsupplies and sucks fluid such as air to and from the first balloon 130,and supplies and sucks fluid such as air to and from the second balloon160. The balloon control device 1100 is constructed by a device body1102 including a pump, a sequencer and the like not shown, and a handswitch 1104 for remote control.

A front panel of the device body 1102 is provided with a power supplyswitch SW1, a stop switch SW2, a pressure gauge 1106 for the firstballoon 130 and a pressure gauge 1108 for the second balloon 160. A tube1110 for supplying/sucking air to and from the first balloon 130, and atube 1120 for supplying/sucking air to and from the second balloon 160are attached to the front panel of the device body 1102. Liquid storingtanks 1130 and 1140 for storing body fluid, which flows backward fromthe first balloon 130 and the second balloon 160 when the first balloon130 and the second balloon 160 are broken, are respectively provided atmidpoints of the respective tubes 1110 and 1120.

Meanwhile, the hand switch 1104 is provided with a similar stop switchSW3 to the stop switch SW2 at the side of the device body 1102, anON/OFF switch SW4 for supporting pressurization/decompression of thefirst balloon 130, a pose switch SW5 for keeping the pressure of thefirst balloon 130, an ON/OFF switch SW6 for supportingpressurization/decompression of the second balloon 160, and a poseswitch SW7 for keeping the pressure of the second balloon 160. This handswitch 1104 is electrically connected to the device body 1102 via acable 1150.

The balloon control device 1100 which is constructed as above suppliesair to the first balloon 130 and the second balloon 160 and inflates thefirst balloon 130 and the second balloon 160, and controls the airpressure at a fixed value to keep the first balloon 130 and the secondballoon 160 in the inflated state. The balloon control device 1100 sucksair from the first balloon 130 and the second balloon 160 and deflatesthe first balloon 130 and the second balloon 160, and controls the airpressure at a fixed value to keep the first balloon 130 and the secondballoon 160 in the deflated state.

Next, an operation method of the endoscope apparatus will be explainedin accordance with FIGS. 15A to 15H.

First, as shown in FIG. 15A, the insertion section 112 is inserted intoan intestinal canal (for example, descending limb of duodenum) 170 inthe state in which the over tube 150 covers the insertion section 112.At this time, the first balloon 130 and the second balloon 160 aredeflated.

Next, as shown in FIG. 15B, in the state in which the tip end 158 of theover tube 150 is inserted up to a bent portion of the intestinal canal170, air is supplied to the second balloon 160 to inflate the secondballoon 160. As a result, the second balloon 160 is caught by theintestinal canal 170, and the tip end 158 of the over tube 150 is fixedto the intestinal canal 170.

Next, as shown in FIG. 15C, only the insertion section 112 of theendoscope 110 is inserted into a deep part of the intestinal canal 170.Then, as shown in FIG. 15D, air is supplied to the first balloon 130 toinflate the first balloon 130. As a result, the first balloon 130 isfixed to the intestinal canal 170. In this case, the first balloon 130is smaller in size at the time of inflation than the second balloon 160,and therefore, the burden exerted on the intestinal canal 170 is small,thus making it possible to prevent damage to the intestinal canal 170.

Next, after air is sucked from the second balloon 160 to deflate thesecond balloon 160, the over tube 150 is pushed in, and inserted alongthe insertion section 112, as shown in FIG. 15E. Then, after the tip end158 of the over tube 150 is pushed into the vicinity of the firstballoon 130, air is supplied to the second balloon 160 to inflate thesecond balloon 160 as shown in FIG. 15F. As a result, the second balloon160 is fixed to the intestinal canal 170. Namely, the intestinal canal170 is gripped by the second balloon 160.

Next, as shown in FIG. 15G, the over tube 150 is drawn in. Thereby, theintestinal canal 170 contracts substantially straight, and excessivedeflection and bending of the over tube 150 are eliminated. When theover tube 150 is drawn in, both the first balloon 130 and the secondballoon 160 are caught in the intestinal canal 170, but the frictionresistance of the first balloon 130 is smaller than the frictionresistance of the second balloon 160. Therefore, even if the firstballoon 130 and the second balloon 160 move to separate from each other,the first balloon 130 with small friction resistance slides with respectto the intestinal canal 170, and therefore, it does not happen that theintestinal canal 170 is damaged by being pulled by both the balloons 130and 160.

Next, as shown in FIG. 15H, air is sucked from the first balloon 130 todeflate the first balloon 130. Then, the tip end part 136 of theinsertion section 112 is inserted into as deep a part of the intestinalcanal 170 as possible. Namely, the insertion operation as shown in FIG.15C is performed again. Thereby, the tip end part 136 of the insertionsection 112 can be inserted into a deep part of the intestinal canal170. When the insertion section 112 is further inserted into a deeppart, the pushing operation as shown in FIG. 15E is performed after thefixing operation as shown in FIG. 15D is performed, and the grippingoperation as shown in FIG. 15F, the drawing-in operation as shown inFIG. 15G, and the inserting operation as shown in FIG. 15H arerepeatedly performed in sequence. Thus, the insertion section 112 can befurther inserted into a deep part of the intestinal canal 170.

During such an operation by the endoscope apparatus, the body fluidflowing backward from the gap between the over tube 150 and theinsertion section 112 flows into the accordion-shaped extendable andcontractible member 152 attached in the watertight state to the base endportion of the over tube 150. The base end portion of theaccordion-shaped extendable and contractible member 152 is fitted ontothe fold prevention part 117 in the watertight state via the ring-shapedfitting member 155 and the packing 159, and therefore, the body fluiddoes not leak out of the base end portion of the accordion-shapedextendable and contractible member 152. Thereby, leakage of the bodyfluid flowing backward from the inside of the intestinal canal can beprevented. The accordion-shaped extendable and contractible member 152extends and contracts in its axial direction, namely, in the insertingdirection of the over tube 150 and the insertion section 112, andtherefore, the inserting operation and the drawing-in operation of theover tube 150 and the insertion section 112 can be performed smoothly.

Further, according to the over tube 150, the accordion-shaped extendableand contractible member 152 is formed to have the length such that thetip end part 158 of the over tube 150 does not contact the first balloon130 when the accordion-shaped extendable and contractible member 152 isextended most as shown in FIG. 14A. As a result, at the stroke end atthe time of insertion of the over tube 150 shown in FIG. 14A, breakageof the first balloon 130 due to contact/abutment of the tip end part 158of the over tube 150 can be prevented.

In the embodiment, the accordion-shaped extendable and contractiblemember 152 with the extending and contracting direction havingdirectivity in one direction is explained, but the form of the memberdoes not matter if only the member is extendable and contractible. Forexample, as shown in FIGS. 16A and 16B, a bag-shaped member 180 havingno directivity in the extending and contracting direction as anextending and contracting member can be applied. In this case, arestraining linear element 182 such as a wire and a string whichrestrains the most extended amount of the bag-shaped member 180 isattached to the bag-shaped member 180 so that the tip end 158 of theover tube 150 does not contact the first balloon 130 at the mostextended time.

Namely, the bag-shaped member 180 is formed into a cylindrical shapewith its both ends opened, and ring-shaped linear element supportmembers 184 and 186 are fixed to the openings at both ends, and both endportions of a plurality of linear elements 182, 182 . . . are fixed tothese linear element support members 184 and 186. The linear element 182is formed to have such length as to prevent the tip end 158 of the overtube 150 from contacting the first balloon 130 when the linear element182 is extended most (the most extended time) as in FIG. 16A. The linearelement support member 184 is fixed to the base end portion of the tubebody 151, and the linear element supporting member 186 is fixed to thering-shaped fitting member 155. Reference character A in FIGS. 16A and16B designates the difference between the most extended time and themost contracted time of the bag-shaped member 180, and referencecharacter B designates a necessary moving amount at the time ofoperation of the endoscope. Reference character C designates a spacebetween the tip end 158 of the over tube 150 and the first balloon 130when the bag-shaped member 180 is contracted most.

FIGS. 17A and 17B show an example in which a drain port 188 is providedat the base end portion side of the accordion-shaped extendable andcontractible member 152. This drain port 188 is provided at a rigid pipebody 190 so that the drain port 188 is not crushed when theaccordion-shaped extendable and contractible member 152 is contracted.The base end portion of the accordion-shaped extendable and contractiblemember 152 is fixed to this pipe body 190, whereby the drain port 188 isprovided to penetrate the base end portion of the accordion-shapedextendable and contractible member 152. This pipe body 190 is fixed tothe ring-shape fitting member 155.

According to the over tube 150 having the drain port 188 like this, byconnecting a suction pump 192 to the drain port 188, the body fluidwhich is stored in a gap between the accordion-shape extendable andcontractible member 152 and the insertion section 112 can be dischargedoutside from the gap by the suction pump 192. Instead of using the pump192, the body fluid stored in the gap can be discharged outside from thedrain port 188 by pumping action which occurs at the time of contractionof the accordion-shaped extendable and contractible member 152.

FIG. 18 shows a system schematic diagram of an endoscope apparatus towhich an insertion assisting tool according to the present invention isapplied. The endoscope apparatus shown in the drawing is constructed byan endoscope 210, an over tube (corresponding to the insertion assistingtool) 250, and a balloon control device 2100.

The endoscope 210 includes a hand operation section 214, and aninsertion section 212 connected to the hand operation section 214. Auniversal cable 215 is connected to the hand operation section 214, anda connecter (not shown) connected to a processor and a light sourcedevice not shown is provided at a tip end of the universal cable 215.

On the hand operation section 214, an air/water passing button 216, asuction button 218, and a shutter button 220 which are operated by anoperator are provided in parallel, and a pair of angle knobs 222 and222, and a forceps insertion section 224 are provided at the respectivepositions. Further, the hand operation section 214 is provided with aballoon air port 226 for supplying air to a first balloon 230 andsucking air from the balloon 230.

The insertion section 212 is constructed by a flexible part 232, acurving part 234 and a tip end part 236. The curving part 234 isconstructed by connecting a plurality of node rings to be able to curve,and is remotely operated to curve by the rotational operation of a pairof angle knobs 222 and 222 provided on the hand operation section 214.Thereby, a tip end surface 237 of the tip end part 236 can be directedin a desired direction.

As shown in FIG. 19, the tip end surface 237 of the tip end part 236 isprovided with an object optical system 238, an illumination lens 240, anair/water passing nozzle 242, a forceps port 244 and the like inpredetermined positions. An air supply/suction port 228 is provided onan outer peripheral surface of the tip end part 236, and this airsupply/suction port 228 communicates with the balloon air port 226 inFIG. 18 via an air supply tube (not shown) with an inner diameter ofabout 0.8 mm which is inserted through the insertion section 212.Accordingly, air is blown out of the air supply/suction port 228 of thetip end part 236 by supplying air into the balloon air port 226, and onthe other hand, air is sucked from the air supply/suction port 228 bysucking air from the balloon air port 226.

As shown in FIG. 18, the first balloon 230 constituted of an elasticbody such as rubber is detachably attached to the tip end part 236 ofthe insertion section 212. The first balloon 230 is formed by a bulgingportion 230 c in a center and attaching portions 230 a and 230 b at bothends of the bulging portion 230 c, and is attached to the tip end part236 side so that the air supply/suction port 228 is located inside thebulging portion 230 c as shown in FIG. 20. The attaching portions 230 aand 230 b are formed to have smaller diameters than the diameter of thetip end part 236, and after being closely fitted onto the tip end part236 with their elastic forces, the attaching portions 230 a and 230 bare fixed with threads not shown wound around the attaching portions 230a and 230 b. The fixation is not limited to the thread winding fixation,but the attaching portions 230 a and 230 b may be fixed to the tip endpart 236 by fitting fixing rings onto the attaching portions 230 a and230 b.

The first balloon 230 fitted onto the tip end part 236 has its bulgingportion 230 c inflated into a substantially spherical shape by blowingair from the air supply/suction port 228 shown in FIG. 19. On the otherhand, by sucking air from the air supply/suction port 228, the bulgingportion 230 c is deflated and is closely fitted onto the outerperipheral surface of the tip end part 236.

The over tube 250 shown in FIG. 18 is formed by a tube body 251, and agripping part 252 to which a tube 280 having the function of a checkvalve is fitted. The tube body 251 is formed into a cylindrical shapeand has a slightly larger inner diameter than an outer diameter of theinsertion section 212, as shown in FIG. 21. The tube body 251 isconstructed by covering an outer side of a flexible resin tube made ofurethane or the like with lubricating coat and covering an inner sidewith the lubricating coat. The insertion section 212 is inserted towardthe tube body 251 from the base end opening 252A of the gripping part252 as shown in FIG. 22.

As shown in FIG. 18, a balloon air port 254 is provided at the base endside of the tube body 251. An air supply tube 256 with an inner diameterof about 1 mm is connected to the balloon air port 254, and this tube256 is bonded to an outer peripheral surface of the tube body 251 and isprovided to extend to a tip end portion of the tube body 251.

A tip end 258 of the tube body 251 is formed into a tapered shape. Asecond balloon 260 constituted of an elastic body such as rubber isfitted onto the base end side of the tip end 258 of the tube body 251.The second balloon 260 is fitted in the state in which the tube body 251penetrates through the balloon 260, and is constructed by a bulgingportion 260 c in a center, and attaching portions 260 a and 260 b atboth ends of the bulging portion 260 c as shown in FIG. 21. Theattaching portion 260 a at the tip end side is folded back to the insideof the bulging portion 260 c, and the attaching portion 260 a that isfolded back is fixed to the tube body 251 with an X-ray contrast thread262 wound around the attaching portion 260 a that is folded back. Theattaching portion 260 b at the base end side is disposed outside thesecond balloon 260, and is fixed to the tube body 251 with a thread 264wound around the attaching portion 260 b.

The bulging portion 260 c is formed into a substantially spherical shapein a natural state (the state in which the bulging portion 260 c doesnot inflate or deflate), and as for the size, the bulging portion 260 cis formed to be larger than the size of the first balloon 230 in anatural state (the state in which the balloon 230 does not inflate ordeflate). Accordingly, when the air is supplied to the first balloon 230and the second balloon 260 at the same pressure, the outer diameter ofthe bulging portion 260 c of the second balloon becomes larger than theouter diameter of the bulging portion 230 c of the first balloon 230.The outer diameter of the second balloon 260 is constructed to be φ50 mmwhen the outer diameter of the first balloon 230 is φ25 mm, for example.

The aforementioned tube 256 is opened in the inside of the bulgingportion 260 c, where an air supply/suction port 257 is formed.Accordingly, when air is supplied from the balloon air port 254, the airis blown from the air supply/suction port 257, and thereby, the bulgingportion 260 c is inflated. When air is sucked from the balloon air port254, the air is sucked from the air supply/suction portion 257, and thesecond balloon 260 is deflated. Reference numeral 266 in FIG. 22designates an inlet port for filling a lubricating liquid such as waterinto the tube body 251, and the inlet port 266 communicates with thebase end portion side of the tube body 251 via a tube 268 with a thindiameter.

Incidentally, the tube 280 shown in FIG. 22 is formed into asubstantially cylindrical shape by an elastic body such as naturalrubber or synthetic rubber. Among openings at both ends of the tube 280,an opening 282 fitted onto the gripping part (the base end portion, atthe side of the hand operation section, of the insertion assisting tool)252 is formed to be smaller than the outer diameter of the base end part253 of the gripping part 252. As a result, the tube 280 is fitted ontothe gripping part 252 in the state in which the opening 282 is expandedin diameter with the elastic force as shown in FIG. 23. Namely, an edgeportion 283 of the opening 282 of the tube 280 is closely fitted onto anouter surface of the gripping part 252 with the elastic force.

Among the openings at the both ends of the tube 280, an opening 284which is fitted onto an outer surface of the insertion section 212 isformed to be smaller than the diameter of the insertion section 212 asshown in FIG. 22. The insertion section 212 is pushed into this opening284 with the tip end part 236 inserted first as shown in FIG. 24A,whereby an edge portion 285 of the opening 284 is extended in diameterwith the elasticity and closely fitted onto the insertion section 212.The diameter of the opening 284 of the tube is set at 70% to 90% of theouter diameter of the insertion section 212. Thereby, the insertionsection 212 is closely fitted to the edge portion 285 of the opening 284with the elasticity and inserted through the opening 284 slidably withrespect to the opening 284.

Meanwhile, the balloon control device 2100 in FIG. 18 is the devicewhich supplies and sucks fluid such as air to and from the first balloon230, and supplies and sucks fluid such as air to and from the secondballoon 260. The balloon control device 2100 is constructed by a devicebody 2102 including a pump, a sequencer and the like not shown, and ahand switch 2104 for remote control.

A front panel of the device body 2102 is provided with a power supplyswitch SW1, a stop switch SW2, a pressure gauge 2106 for the firstballoon 230 and a pressure gauge 2108 for the second balloon 260. A tube2110 for supplying/sucking air to and from the first balloon 230, and atube 2120 for supplying/sucking air to and from the second balloon 260are attached to the front panel of the device body 2102. Liquid storingtanks 2130 and 2140 for storing body fluid, which flows backward fromthe first balloon 230 and the second balloon 260 when the first balloon230 and the second balloon 260 are broken, are respectively provided atmidpoints of the respective tubes 2110 and 2120.

Meanwhile, the hand switch 2104 is provided with a similar stop switchSW3 to the stop switch SW2 at the side of the device body 2102, anON/OFF switch SW4 for supporting pressurization/decompression of thefirst balloon 230, a pose switch SW5 for keeping the pressure of thefirst balloon 230, an ON/OFF switch SW6 for supportingpressurization/decompression of the second balloon 260, and a poseswitch SW7 for keeping the pressure of the second balloon 260. This handswitch 2104 is electrically connected to the device body 2102 via acable 2150.

The balloon control device 2100 which is constructed as above suppliesair to the first balloon 230 and the second balloon 260 and inflates thefirst balloon 230 and the second balloon 260, and controls the airpressure at a fixed value to keep the first balloon 230 and the secondballoon 260 in the inflated state. The balloon control device 2100 sucksair from the first balloon 230 and the second balloon 260 and deflatesthe first balloon 230 and the second balloon 260, and controls the airpressure at a fixed value to keep the first balloon 230 and the secondballoon 260 in the deflated state.

Next, an operation method of the endoscope apparatus will be explainedin accordance with FIGS. 25A to 25H.

First, as shown in FIG. 25A, the insertion section 212 is inserted intoan intestinal canal (for example, descending limb of duodenum) 270 inthe state in which the over tube 250 covers the insertion section 212.At this time, the first balloon 230 and the second balloon 260 aredeflated.

Next, as shown in FIG. 25B, in the state in which the tip end 258 of theover tube 250 is inserted up to a bent portion of the intestinal canal270, air is supplied to the second balloon 260 to inflate the secondballoon 260. As a result, the second balloon 260 is caught in theintestinal canal 270, and the tip end 258 of the over tube 250 is fixedto the intestinal canal 270.

Next, as shown in FIG. 25C, only the insertion section 212 of theendoscope 210 is inserted into a deep part of the intestinal canal 270.Then, as shown in FIG. 25D, air is supplied to the first balloon 230 toinflate the first balloon 230. As a result, the first balloon 230 isfixed to the intestinal canal 270. In this case, the first balloon 230is smaller in size at the time of inflation than the second balloon 260,and therefore, the burden exerted on the intestinal canal 270 is small,thus making it possible to prevent damage to the intestinal canal 270.

Next, after air is sucked from the second balloon 260 to deflate thesecond balloon 260, the over tube 250 is pushed in, and inserted alongthe insertion section 212, as shown in FIG. 25E. Then, after the tip end258 of the over tube 250 is pushed into the vicinity of the firstballoon 230, air is supplied to the second balloon 260 to inflate thesecond balloon 260 as shown in FIG. 25F. As a result, the second balloon260 is fixed to the intestinal canal 270. Namely, the intestinal canal270 is gripped by the second balloon 260.

Next, as shown in FIG. 25G, the over tube 250 is drawn in. Thereby, theintestinal canal 270 contracts substantially straight, and excessivedeflection and bending of the over tube 250 are eliminated. When theover tube 250 is drawn in, both the first balloon 230 and the secondballoon 260 are caught in the intestinal canal 270, but the frictionresistance of the first balloon 230 is smaller than the frictionresistance of the second balloon 260. Therefore, even if the firstballoon 230 and the second balloon 260 move to separate from each other,the first balloon 230 with small friction resistance slides with respectto the intestinal canal 270, and therefore, it does not happen that theintestinal canal 270 is damaged by being pulled by both the balloons 230and 260.

Next, as shown in FIG. 25H, air is sucked from the first balloon 230 todeflate the first balloon 230. Then, the tip end part 236 of theinsertion section 212 is inserted into as deep a part of the intestinalcanal 270 as possible. Namely, the insertion operation as shown in FIG.25C is performed again. Thereby, the tip end part 236 of the insertionsection 212 can be inserted into a deep part of the intestinal canal270. When the insertion section 212 is further inserted into a deeppart, the pushing operation as shown in FIG. 25E is performed after thefixing operation as shown in FIG. 25D is performed, the grippingoperation as shown in FIG. 25F and the drawing-in operation as shown inFIG. 25G, and the inserting operation as shown in FIG. 25H arerepeatedly performed in sequence. Thus, the insertion section 212 can befurther inserted into the deep part of the intestinal canal 270.

During such an operation, the body fluid which flows backward from thegap between the tube body 251 of the over tube 250 and the insertionsection 212 (see FIG. 21) due to internal pressure of the intestinalcanal 270 is stored in the tube 280 without leaking out of the tube 280because the edge portion 283 of the opening 282 of the tube 280 isattached to be closely fitted onto the gripping part 252 by the elasticforce and the edge portion 285 of the opening 284 of the tube 280 isattached to be closely fitted onto the insertion section 212 by theelastic force as shown in FIG. 24A, and thus, the tube 280 exhibits thefunction of the check valve. As a result, leakage of the body fluid canbe prevented.

In order to improve slip property of the insertion section 212 withrespect to the over tube 250, in the over tube 250 shown in FIG. 18, alubricating liquid is supplied to the over tube 250 from the inlet port266 via the tube 268. By storing the lubricating liquid in the tube 280and allowing the tube 280 have the pot function, it is made possible tofill the lubricating liquid in the gap between the over tube 250 and theinsertion section 212. As a result, favorable slip property can bealways obtained. Further, by the lubricating liquid pot function of thetube 280, the supply amount and the number of times of supply of thelubricating liquid from the inlet port 266 can be reduced.

Incidentally, in the endoscope apparatus including the over tube 250,the insertion section 212 is inserted into the base end portion of thegripping part 252 with some degree of freedom with respect to the baseend portion as shown in FIG. 22 in consideration of operability ofinsertion and extraction of the insertion section 212 with respect tothe over tube 250. Namely, a space S between the gripping part 252 andthe insertion section 212 is set to be comparatively larger than spacesat the other positions, and insertion and extraction operability of theoperator is enhanced by making the insertion and extraction direction ofthe insertion section 212 properly changeable by using the space S.Accordingly, in the case where the tube 280 is fitted onto the insertionsection 212, it is also necessary to keep the insertion and extractionoperability.

Thus, the tube 280 of this embodiment is formed in the size whichsatisfies the formula d>a−c+(b−a)/2, where the inner diameter of thegripping part 252 of the over tube 250 is a, the maximum diameter of thetube 280 when the tube 280 is attached to the gripping part 252 (theouter diameter of the base end part 253 of the gripping part 252) is b,the diameter of the opening 284 of the tube 280 is c, and the shortestdistance from the fixed portion B of the tube 280 to the gripping part252 to the edge portion 285 of the opening 284 of the tube 280 is d asshown in FIG. 26. Namely, as shown by the chain double-dashed line inFIG. 26, the distance d is set to be longer than the distance e which isfrom the fixed portion 252B to the insertion section 212 when theinsertion section 212 is put aside as much as possible by using thespace S (see FIG. 22).

As a result, even when the insertion section 212 is put aside as much aspossible by using the space S, slackness occurring to a circular conicalportion 281 (see FIG. 22) which is the length d portion of the tube 280does not disappear. Therefore, at the time of insertion and extractionoperation using the space S of the tube 280 as shown in FIGS. 24B and24C, the insertion section 212 does not receive any compelling forcefrom the circular conical portion 281, and therefore, insertion andextraction operability can be maintained.

In the embodiment, the over tube which is used for inspection of a smallintestine is explained as the insertion assisting tool, but the presentinvention is not limited to this, and tube 280 may be fitted onto asliding tube which is used for inspection of a large intestine.

1-5. (canceled)
 6. The insertion assisting tool for an endoscope ofclaim 12, further comprising: a cylindrical extendable and contractiblemember connecting respective base end parts of the insertion section ofthe endoscope and the insertion assisting tool in which the insertionsection of the endoscope is inserted, said cylindrical extendable andcontractible member covering the insertion section.
 7. The insertionassisting tool for an endoscope according to claim 6, wherein theextendable and contractible member is an accordion-shaped member.
 8. Theinsertion assisting tool for an endoscope according to claim 6, whereinthe extendable and contractible member is formed to have length by whicha tip end part of the insertion assisting tool does not contact a firstballoon of the insertion section when the extendable and contractiblemember is operated to extend most.
 9. The insertion assisting tool foran endoscope according to claim 6, wherein a drain port is formed at theextendable and contractible member.
 10. An insertion assisting tool foran endoscope into which an insertion section of the endoscope isinserted, comprising: a substantially cylindrical tube formed of anelastic body in which a smaller opening than a diameter of a base endpart of the insertion assisting tool is formed at one end and a smalleropening than a diameter of the endoscope insertion section is formed atthe other end, wherein in the tube, the opening formed at the one end isattached to the base end part of the insertion assisting tool in closecontact with the base end part, and the insertion section is slidablyinserted through the tube with the insertion section of the endoscopeclosely fitted in the opening formed at the other end.
 11. The insertionassisting tool for an endoscope according to claim 10, wherein the tubeis formed in a size which satisfies a formula ofd>a−c+(b−a)/2 where an inner diameter of the insertion assisting tool isa, a maximum diameter of the tube when the tube is attached to theinsertion assisting tool is b, a diameter of an opening formed at theother end of the tube is c, and a distance from a fixing portion of thetube to the insertion assisting tool to an edge portion of the openingformed at the other end of the tube is d.
 12. An insertion assistingtool for an endoscope into which an insertion section of the endoscopeis inserted from a base end portion side, comprising: a fluid sealingdevice disposed at the base end portion side which seals a space betweena base end part of the insertion assisting tool and the endoscopeinsertion section, the space being formed while the insertion section ofthe endoscope is inserted into the insertion assisting tool, whereinsaid fluid scaling device connects respective base end portions of theinsertion section of the endoscope and the insertion assisting tool andis cover member which covers the insertion section of the endoscope suchthat directions of insertion and drawing-in of the insertion section ofthe endoscope are changeable pivotally.